Fossil Rim Wildlife Center is the greatest day trip from Dallas! It was so much fun, I would definitely visit every time we go to Dallas. Having giraffes eat from your hand is just too cool. But watch out for the bull giraffe, he's a slobbery one!
If you are in to scantily-clad waitstaff, then I guess Bone Daddy's: House of Smoke could be considered a highlight. Mike's comment was, "Wow! They wear even less than the Hooters girls!" Yes, that's why I love him.
Quick Tips:
Weather, of course, check The Weather Channel before you arrive. But also call the hotels or people you will be staying with. The Weather Channel was reporting thunderstorms and tornadoes, so we didn't think to pack hats and sunscreen. Sure enough, our first day was sunny and 82 degrees, but we were in Glen Rose, not Dallas.
Best Way To Get Around:
Car - I love public transportation, but not in Dallas. Renting a car is your best best. And there is a gas station right before you enter the car rental area as you return to DFW so don't even think about using the rental agencies prepay fuel option.
Defensive Driving - I've read articles about how bad traffic is in Seattle and San Francisco, but I have never been so scared on the road as when I an in Dallas. Speed limits do not apply, crossing over several lanes in the span of 50 feet is commonplace, and never expect that another car is going to let you into their lane. Dallas is not for the faint of heart, drive aggressively and with an awareness of where your exits are.
Tollways - Have plenty of change ready for the toll stations. I heard a rumor that they were removing the booths on the tollways in Dallas, but everywhere we passed through still had a lane for exact change or a manned booth.
Directions - As always, I mapped our route using AAA's TripTiks online. We only had two errors which were only that the destination was on the opposite of the street. You don't need to be a member to use the basic features.